Tiêu đề NT 22 PAPER.pdf ✅

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PHYSICS Section-A 1. Two point masses m and 3m are placed at distance r. The moment of inertia of the system about an axis passing through the center of mass of system and perpendicular to the line joining the point masses is (A) 3 2 mr 5 (B) 3 2 mr 4 (C) 3 2 mr 2 (D) 6 2 mr 7 2. Total energy of a satellite revolving around earth is –8.4 × 1013 J. Then find additional energy required to send the satellite to infinity is : (A) 4.2 × 1013 J (B) 16.8 × 1013 J (C) 8.4 × 1013 J (D) Not possible 3. Initially both blocks A and B stay at equilibrium. If string between A and B is cut, then acceleration of block A and B just after cut will be : (A) g downward, g upward (B) g/2 downward, zero (C) g downward, g downward (D) g/2 downward, g upward 4. A vehicle is moving on a track with constant speed as shown in figure. The apparent weight of the vehicle is (A) Maximum at A (B) Maximum at B (C) Maximum at C (D)Same at A, B and C 5. Water is flowing through a channel (lying in a vertical plane) as shown in the figure. Three sections A, B and C are shown. Sections B and C have equal area of cross section. If PA, PB and PC are the pressures at A, B and C respectively then h B C A (A) PA > PB = PC (B) PA < PB = PC (C) PA < PB = PC (D) PA < PB < PC 6. A torque T acts on a body of moment of inertia l rotating with angular speed . It will be stopped just after time (A) lT  (B) l T  (C) T l  (D) lT 7. The moment of inertia of body depends on (A) The mass of the body (B) The distribution of the mass in the body (C) The axis of rotation of the body (D) All of these 8. A wheel starts from rest and attains an angular velocity of 20 radian/s after being uniformly accelerated for 10 s. The total angle in radian through which it has turned in 10 second is (A) 20 (B) 40 (C) 100 (D) 100 9. A solid sphere, a spherical shell, a ring and a disc of same radius and mass are allowed to roll down an smooth inclined plane without slipping. The one which reaches the bottom first is (A) Solid sphere (B) Spherical shell (C) Ring (D) Disc PW – AITS_NT-22
10. The vibrations of two air column under identical conditions are represented in the figure below. The ratio of frequencies na : nb will be (a) (b) (A) 2 : 3 (B) 3 : 2 (C) 3 : 4 (D) 1 : 2 11. A block of mass 6 kg is initially at rest on the ground. An agent slowly lifts the block to a height 30m above the ground in time 20s. Average power delivered by the agent is equal to (A) 30 Watt (B) 60 Watt (C) 90 Watt (D) 1800 Watt 12. The molecules of a given mass of a gas have a r.m.s. velocity of 200 m/sec at 27°C and 1.0 × 105 N/m2 pressure. When the temperature is 127°C and pressure is 0.5 × 105 N/m2 , the r.m.s. velocity in m/sec will be (A) 100 2 3 (B) 100 2 (C) 400 3 (D) None of these 13. A solid cube of side 10 cm is fixed at it’s base. On it’s top surface a tangential force 100 N is applied as a result the top surface gets shifted through 2 mm w.r.t. the bottom surface. Modulus of rigidity of the solid is (A) 6 2 5 10 Nm−  (B) 5 2 5 10 Nm−  (C) 7 2 5 10 Nm−  (D) 8 2 5 10 Nm−  14. A cube and a sphere made of same material shown in figure are allowed to cool under identical conditions, then 10 cm 10 cm (A) Cube will cool at a faster rate (B) Sphere will cool at a faster rate (C) Rate of cooling independent of dimension of body (D) Both (B) & (C) correct. 15. Zeroth law of thermodynamics is mainly concerned with (A) Work done by a system in an thermodynamic process (B) Thermal equilibrium of two bodies (C) Change in internal energy of a system in a thermodynamic process (D) Redistribution of internal energy between two parts of a system 16. One mole of a perfect gas in a cylinder fitted with a piston has a pressure p, volume V and temperature T. If the temperature is increased by 1 K keeping pressure constant, the increase in volume is (A) 2V 273 (B) V 91 (C) V 273 (D) V 17. A helium nucleus makes a full rotation in a circle of radius 0.8 metre in 2 sec. The value of the magnetic field induction B in tesla at the centre of circle will be : (A) 2 × 10–19 0 (B) 10–19 /0 (C) 10–19 0 (D) 2 × 10–20/0 18. A circular current loop of magnetic M is in an arbitrary orientation in an external magnetic field B. The work done to rotate the loop by 30° about an axis perpendicular to its plane is : (A) MB (B) MB 3 2 (C) MB 2 (D) Zero 19. The charge supplied by the battery in the circuit shown in the figure (A) 300μC 11 (B) 60 C (C) 50 C (D) 110 C 5 F 6 F 10 V
20. The electrical potential at a point (x, y, z) is given by V = –x 2y – xz3 + 4. The electric field E at that point is (A) E (2xy z )i x j 3xz k 3 2 2 ˆ ˆ ˆ = + + + (B) ˆ ˆ ˆ 2 2 2 E 2xyi (x y )j (3xz y )k = + + + − (C) E z j xyzi 3z xk 3 2 ˆ ˆ ˆ = + + (D) E (2xy z )i xy j 3z xk 3 2 3 ˆ ˆ ˆ = − + + 21. The variation of electric field between the two charges q1 and q2 along the line joining the charges is plotted against distance from q1 (taking rightward direction of electric field as positive) as shown in the figure. Then the correct statement is (A) q1 and q2 are positive and |q1| > |q2| (B) q1 and q2 are positive and |q1| < |q2| (C) q1 positive and q2 is negative |q1| < |q2| (D) q1 negative and q2 is positive |q1| > |q2| 22. According to modified Ampere’s circuital law (iD = displacement current) (A) E 0 C 0 d B.dl i dt    =  +       (B) E 0 0 d B.dl dt  =    (C)  B.dl i = 0 (D) E 0 C D d B.dl i i dt    =  +      23. For a given circuit find potential difference across 8 if current in 12 is 3 Amp. 3 12 8 I = 3Amp (A) 120 V (B) 24 V (C) 96 V (D) 16 V 24. A Potentiometer wire has length 10 m and resistance 8 . The resistance that must be connected in series with the wire and main battery of emf 20V, so as to get a potential gradient 1.6V per m on the wire (A) 44 (B) 2 (C) 3 (D) 8 25. Power generated across a uniform wire connected across a supply is H. If the wire is cut into n equal parts and all the parts are connected in parallel across the same supply, the total power generated in the wire is (A) 2 H n (B) n2H (C) nH (D) H n 26. An e.m.f. of 15 V is applied in a circuit coil containing 5 henry inductance and 10 ohm resistance. The ratio of current at time t =  and t = 1 second is (A) 1 2 1 2 e e 1− (B) 2 2 e e 1− (C) 1 2 e e 1− (D) 1 2 e e 1 + 27. In a transistor 108 electrons enter at the emitter in 10–4 s, out of which 2% electron go to the base. What is the current transfer ratio in common base configuration? (A) 98 (B) 2 (C) 0·98 (D) 0·2 28. Three ideal diodes are connected to the battery as show in the circuit. The current supplied by the battery is 40V 20 10 D3 D2 D1 (A) Zero (B) 4 A (C) 2 A (D) 6 A 29. The wavelength of the first line of Balmer series of hydrogen atom is . What will be the wavelength of the same line in doubly ionized lithium? (A) /2 (B) /9 (C) /8 (D) /27 q1 q2 r